Device for displaying a seat component

ABSTRACT

To adjust a component ( 17 ) of a seat ( 14 ), and particularly a seat ( 14 ) in a motor vehicle, use is made of an adjusting device ( 28, 29 ) which has a rotary drive ( 8 ) and a gearbox. The gearbox comprises a planetary gear train having a sunwheel ( 7 ) driven by the rotary drive ( 8 ), at least one planetary gear ( 4 ) mounted to rotate on a planetary gear carrier ( 6 ) and a fixed annular gear ( 1 ). The at least one planetary gear ( 4 ) meshes with the sunwheel ( 7 ) and the annular gear ( 1 ). The output of the gearbox is taken from the planetary gear carrier ( 6 ), which takes the particular form of a cable drum so that the adjustment of the component of the seat can be performed by means of a traction cable secured to the cable drum which can be wound up thereon. With the help of a gearbox of this form it is possible to achieve a particularly small size, which substantially simplifies the fitting of the adjusting device ( 28, 29 ) into a seat ( 14 ).

This application claims priority to PCT/EP02/11975 filed on Oct. 25,2002; which claims priority to German Patent DE10154186.4, filed on Nov.5, 2001.

The present invention relates to a device for adjusting a component of aseat or lounger, having a rotary drive and a gearbox able to be drivenby the rotary drive which has an output for adjusting the component ofthe seat or lounger.

Seats and loungers are often fitted with various adjustment facilitiesto increase the comfort in which people can sit or lie on them. By usingthe adjustment facilities it is possible to adjust a seat or lounger tothe varying needs of a person sitting or lying on it. These needs maydepend on for example the physical characteristics of the person or theactivity the person is performing. One possible adjustment of this kindis for example setting the angle between the seat proper of a seat andits backrest. In general terms, provision may be made for a seat orlounger to be divided into various segments and for it to be possiblefor the angle between two adjacent segments to be altered.

As well as possible adjustments of this kind which affect the externalshape of a seat or lounger, provision may also be made for adjustmentswhich affect the way in which it acts with a person sitting or lying onit. These include supports incorporated in the seat or lounger whichsupport the person at certain points and which can be adjusted inrespect of, for example, their position and shape.

To allow an adjustment to be made to a seat or lounger, suitableadjusting devices are needed which can be operated manually or by amotor.

In this way, there is known from EP-0 696 251 B1 a device for adjustingthe height and/or curvature of a lumbar support having a gearbox drivenby a drive, in which the drive drives a worm which engages in a wormwheel, which in turns drives a pinion which meshes with a gear driving areel. Fastened to the reel is the inner traction cable of a Bowden cablearrangement which is used to adjust the lumbar support. The gear drivingthe reel has a land which co-operates with stops in the housing of thegearbox to limit the adjusting travel of the adjusting device. Theparticular disadvantage that this adjusting device has is that the partswhich are needed in the gearbox take up a considerable amount of roomand this has an adverse effect as far as fitting the gearbox into a seator lounger is concerned. It has a particularly adverse effect as far asfitting an adjusting device of this kind into a seat for a motor vehicleis concerned, in which small dimensions are a requirement because ofother components which are present and the small amount of spaceavailable.

The object of the present invention is to provide an adjusting device ofthe kind specified above which, though low in cost, requires only asmall amount of space.

In accordance with the invention, this object is achieved by anadjusting device which has the features detailed in claim 1. Thesubclaims each define preferred and advantageous embodiments of thepresent invention.

The adjusting device according to the invention has planetary gearing ofwhich the sunwheel is driven by the rotary drive by means of wormgearing. The sunwheel is centrally located within an annular gear, therebeing arranged between the sunwheel and the annular gear at least oneplanetary gear which meshes both with the sunwheel and with the annulargear. The at least one planetary gear is mounted to rotate on aplanetary gear carrier which in turn is mounted to rotate concentricallywith the sunwheel. In an arrangement like this, the wormwheel, theannular gear and the planetary wheel carrier are arranged concentricallyto one another, thus giving a size which is reduced in comparison withthe prior art. This is possible because, in particular, the worm gearand the annular gear are the two gears of largest diameter in thegearbox. Because it is precisely the large gears which areconcentrically arranged, the layout which is obtained is more compact.

If, in the adjusting device according to the invention, it is desired tolimit the adjusting travel, this can advantageously be done by providingthe annular gear with internal teeth for only part of its circumference.The rest of the circumference of the annular gear is so designed thatthe planetary gear can roll only on the part which has internal teeth.This can for example be done by having the non-internally-toothed partproject sufficiently far in the direction of the sunwheel for the teethof the planetary gear to abut against the non-internally-toothed part assoon as they reach it. In this way it is possible to limit the adjustingtravel of the adjusting device at particularly low cost, with thismethod of limiting having the advantage that the abutting against alimiting means does not cause much unpleasant noise. Any desired numberof planetary gears can be used in the planetary gearing, the maximumnumber of gears that is possible depending in particular on thetransmission ratio of the planetary gearing, the force the planetarygearing has to transmit and any limit that is desired to the adjustingtravel of the adjusting device. At the same time, the cost of producingthe adjusting device rises with the number of planetary gears, though asthe number of planetary gears rises a better load distribution isobtained within the planetary gearing. If part of the annular gear isproduced without internal teeth in order to limit the adjusting travelof the adjusting device, the maximum possible range of rotation of theplanetary gear carrier is the angular range between two adjacentplanetary gears. It is therefore advantageous for the planetary gearingto have only one planetary gear, which means that when limits areapplied a maximum range of rotation of almost 360° is possible and thereis thus a great deal of freedom as to the limited range of rotation.

Advantageously, the sunwheel is driven by a wormwheel with which a wormdriven by the rotary drive engages. The advantage this has is that ahigh reduction ratio is obtained from only a single stage of gearing andin particular that any feedback of force from the adjustable seat orlounger component to the rotary drive is obviated. In this way therotary drive is able, when stationary, to hold the adjustable componentin the position to which it has been adjusted at the time, even if thecomponent exerts a force on the gearing.

The output from the gearing which is used is advantageously a drum towhich a traction cable is connected and onto which it can be wound. Bymeans of a traction cable of this kind, an adjusting movement can berouted from the rotary drive to another point with particularly littlecost and complication. The traction cable is advantageously guided in aBowden cable arrangement.

Particularly when a traction cable is used, a return spring can befitted which exerts a force on the adjustable component in the oppositedirection to the tractive action of the traction cable.

The adjusting device according to the invention is suitable withparticular advantage for adjusting a lumbar support in the backrest of aseat or lounger. In this case the lumbar support can be adjustable bothin respect of its position in the backrest and in respect of its shape.Advantageously the lumbar support is positioned centrally in thebackrest and is adjustable heightwise, thus enabling allowance to bemade for seated persons with backs of different lengths.

The adjustment of the shape of a lumbar support is advantageouslyeffected with the help of a curving member whose curvature isadjustable. A curving member of this kind may in particular have atleast one strip which is resilient in bending and of which two spacedsections are drawn towards one another so that the strip arches. By thissimple drawing together of the strip at two different points it is thuspossible to obtain a settable curvature for the lumbar support at onlylow cost and complication.

The invention is explained in detail below by reference to a preferredembodiment and to the accompanying drawings.

FIG. 1 is a diagrammatic sectional view from the side of a seat for usein a motor vehicle,

FIG. 2 shows a lumbar support arranged in the seat shown in FIG. 1,

FIG. 3 is a partial plan view of an adjusting device used for adjustingthe lumbar support shown in FIG. 2, and

FIG. 4 is a sectional view from the side through the gearbox of theadjusting device shown in FIG. 3.

The seat 14 shown diagrammatically in FIG. 1 is intended for use in amotor vehicle and has a seat section 15 and a rest 16 connected theretoto hinge. Arranged in the rest 16 below padding is a lumbar support 17by which additional support can be provided at a certain point for thespinal column of a person sitting on the seat 14.

To enable the lumbar support 17 to be matched to the particularrequirements of a person sitting on the seat 14, the lumbar support 17can be adjusted in respect of its heightwise position in the rest 16.For this purpose the lumbar support 17 is guided to be longitudinallydisplaceable within the rest 16 at the centre of the latter. It is alsopossible for the pressure from the lumbar support 17 which acts in theforward direction to be set in order to vary its supporting action.

The lumbar support 17 which is shown from the front in FIG. 2 has aframe 18 for fastening into the rest 16, to which the other parts of thelumbar support 17 are attached. Between the two longitudinals of frame18 two resiliently bendable longitudinal strips 24 are arranged whichare connected together by spaced transverse strips 19. Fastened to thetop end of the longitudinal strips 24 is a top terminating strip 20 andto the bottom end of the longitudinal strips 24 a reinforcing plate 21is fastened. Top terminating strip 20 and reinforcing plate 21 aremounted to be longitudinally displaceable on two longitudinal rods 22which extend parallel to longitudinal strips 24. Longitudinal rods 22are connected to frame 18 at their top and bottom ends by transverserods 23.

The bottom transverse rod 23 is connected to reinforcing plate 21 by acoil spring 25. As a result, reinforcing plate 21, together withlongitudinal strips 24, transverse strips 19 and top terminating strip20, can be moved upwards along longitudinal rods 22 by upwardly directedtraction.

Longitudinal strips 24 and the mounting for them on longitudinal rods 22by means of top terminating strip 20 and reinforcing plate 21 are sodesigned that if top terminating strip 20 and bottom reinforcing plate21 are pressed towards one another, longitudinal strips 24 will archforwards against the back of a person sitting on seat 14.

Fastened to the bottoms of respective longitudinals of frame 18 are acurvature adjusting means 28 and a heightwise adjusting means 29.Curvature adjusting means 28 is connected in this case via a Bowdencable 26 to top terminating strip 20 and reinforcing plate 21. Inside ofit the Bowden cable 26 has a traction cable 30 which is connected toreinforcing plate 21. The casing of Bowden cable 26 on the other hand issupported against top terminating strip 20. If curvature adjusting means28 then pulls traction cable 30 through the casing of Bowden cable 26and towards itself, top terminating strip 20 and reinforcing plate 21are drawn towards each other, whereupon the curvature of longitudinalstrips 24 becomes more pronounced. If curvature adjusting means 28slackens off, traction cable 30 is pulled back by the resilient forceexerted by the two longitudinal strips 24.

Heightwise adjusting means 29 acts via a Bowden cable 27 which has acasing with a traction cable 31 inside it. The casing of Bowden cable 27is supported from the top transverse bar 23 and traction cable 31 of theheightwise adjusting means is connected to reinforcing plate 21. Ifheightwise adjusting means 29 then draws traction cable 31 towardsitself, reinforcing plate 21 is drawn upwards in opposition to the forceexerted by coil spring 25. If heightwise adjusting means 29 relaxestraction cable 31, reinforcing plate 21 is pulled downwards by coilspring 25. Since top terminating strip 20 is mounted to move by slidingon the two longitudinal rods 22, the two curved longitudinal strips 24can be moved up or down together with the cross-members 19 fastened tothem.

Curvature adjusting means 28 and heightwise adjusting means 29 are bothconstructed in the same way and they are shown diagrammatically in FIGS.3 and 4. The two adjusting devices 28, 29 each have a motor 8 to act astheir rotary drive and, fastened thereto, a gearbox which acts ontraction cable 30 or 31 as the case may be. FIG. 3 is a partial planview of the gearbox and motor. FIG. 4 is a view in section of thegearbox and part of the motor 8.

The gearbox which is shown in section in FIG. 4 has a housing 1 which isconnected to motor 8. A top cover 2 and a bottom cover 3 can be fastenedto the two side of housing 1. The two covers 2, 3 have opposingconcentric seatings which are used to support the gears arranged inhousing 1. Arranged inside housing 1 is a wornwheel 9 which is providedwith external teeth and which encloses within it and in such a way as tobe secured to it in rotation a sunwheel 7 which projects beyondwormwheel 9 on the right. Arranged next to sunwheel 7 on the rightconcentrically thereto is a cable pulley 6 which carries a groove aroundits circumference. Formed on the right of cable pulley 6 is a hub bymeans of which it is mounted in an opening in top cover 2. Cable pulley6 also has, in the centre, a bore in which is mounted a shaft 11 onwhich sunwheel 7 is mounted and whose end opposite from cable pulley 6is mounted in bottom cover 3 by means of a bush.

Mounted to rotate on cable pulley 6 via a pin 5 is a planetary gear 4which is located between cable pulley 6 and wormwheel 9. Planetary gear4 meshes with sunwheel 7. Formed in housing 1 in the plane of planetarygear 4 is an annular gear having internal teeth, with which planetarygear 4 also meshes. Together with the annular gear formed in housing 1,planetary gear 4 and the cable pulley 6 which acts as a planetary gearcarrier, sunwheel 7 forms a planetary gear train whose input is sunwheel7 and whose output is cable pulley 6.

In the plan view of the gearbox shown in FIG. 3, wormwheel 9 and a worm12 which engages with wormwheel 9 are indicated in broken lines. Theworm 12 is connected to the shaft of motor 8 to be secure in rotationtherewith and drives wormwheel 9. In the plan view shown in FIG. 3, partof top cover 2 has been removed. In the area thus revealed a leadthrough13 can be seen which is situated in the plane of the groove in cablepulley 6 and which is aligned tangentially to said groove. Leadthrough13 serves to lead traction cable 30 or 31 through, which can be fastenedto cable pulley 6 and can be wound up in its groove. On the outsideleadthrough 13 ends in an abutment for the casing of Bowden cable 26 or27.

When curvature adjusting means 28 or heightwise adjusting means 29 isactuated, motor 8 drives the worm in the direction of rotation whichturns wormwheel 9 and the sunwheel 7 fastened thereto. The rotation ofsunwheel 7 causes planetary gear 4 to roll in the annular gear formed inhousing 1, thus causing cable pulley 6 to be turned as well by means ofpin 5. Cable pulley 6 in turn pulls on traction cable 30 or 31 and inthis way produces the adjustment.

In the stationary state it is true that a tensile force acts on cablepulley 6 via traction cable 30 or 31 but due to the self-locking actionof worm gearing 9, 12 this force does not result in the shaft of motor 8being turned. Hence no additional locking devices are required to holdthe two adjusting devices 28, 29 in the position they are in at the timewhen the motor 8 is not excited.

The two adjusting devices 28, 29 are each fitted with limiting means togive a defined range of adjustment. The purpose of these limiting meansis to prevent damage to lumbar support 17 and to produce definedadjusted positions. To limit the range of adjustment, the annular gearformed in housing 1 has internal teeth around only part of itscircumference. The remaining part of its circumference on the other handprojects sufficiently far towards sunwheel 7 to make it impossible forplanetary gear 4 to roll into this region. As soon as planetary gear 4reaches an end of this region, at least one of its teeth abuts againstthe region and stops cable pulley 6 from moving any farther. Because ofthe external teeth on planetary gear 4 which roll on the internal teethin the annular gear in housing 1, only a very small amount of noise isproduced at the abutment against the non-toothed part of the annulargear, which is an advantage. The design according to the invention ofthe gearbox in the adjusting devices 28, 29 allows a very small amountof noise to be produced, particularly when the abutments are reached,and this is advantageous in making adjusting devices 28, 29 pleasant tooperate.

1. A device for adjusting a component (17) of a seat (14) or a lounger,comprising: a rotary drive; and a gearbox able to be driven by therotary drive which has an output for adjusting the component (17) of theseat (14) or lounger, wherein said gearbox comprises a planetary geartrain with a sunwheel (7) able to be driven by the rotary drive (8), aplanetary gear carrier (6) mounted to rotate concentrically with thesunwheel (7) and having at least one planetary gear (4) rotatablymounted thereto, and an internally toothed annular gear (1), the annulargear (1) being arranged concentrically to the sunwheel (7), the at leastone planetary gear (4) engaging with the sunwheel (7) and the annulargear (1) and the output of the gearbox being drivable by the planetarygear carrier (6).
 2. The device according to claim 1, wherein theannular gear (1) is internally toothed for a portion of itscircumference in order to limit the range of adjustment of the component(17), the non-internally-toothed part of the annular gear (1) being sodesigned that the planetary gear (4) can roll on the annular gear (1)only in the internally toothed part of the annular gear (1).
 3. Anadjustment device comprising: a rotary drive; and a gearbox in a drivenrelationship with said rotary drive, wherein said gearbox comprises asunwheel, an annular gear, a planetary gear and a planetary gearcarrier, wherein said sunwheel is driven by said rotary drive; saidplanetary gear carrier rotates concentrically with said sunwheel; andsaid planetary gear meshes with said sunwheel and said annular gear. 4.The adjustment device according to claim 3, wherein said planetary gearcarrier is further comprised of a cable pulley.
 5. The adjustment deviceaccording to claim 3, further comprising an adjustment mechanism inoperative communication with said gearbox.
 6. The adjustment deviceaccording to claim 3, wherein said adjustment mechanism is a cable. 7.The adjustment device according to claim 3, wherein a range ofadjustment provided by said gearbox is limited.
 8. The adjustment deviceaccording to claim 3, wherein said annular gear is an internally toothedannular gear.
 9. The adjustment device according to claim 8, whereinsaid annular gear is internally toothed for a portion of itscircumference.
 10. The adjustment device according to claim 9, whereinsaid planetary gear rolls on said internally toothed portion of saidannular gear and does not roll on a non- internally-toothed portion ofsaid annular gear.
 11. The adjustment device according claim 3, furthercomprising a plurality of planetary gears.
 12. The adjustment deviceaccording to claim 3, further comprising a wormwheel connected to saidsunwheel, said sunwheel in rotation with said wormwheel
 13. Theadjustment device according to claim 12, further comprising a wormconnected to said rotary drive, wherein said wormwheel engages with saidworm.
 14. The adjustment device according to claim 13, wherein saidrotary drive further comprises a shaft in solid rotation with said worm.15. The adjustment device according to claim 3, further comprising acable pulley operatively connected to said planetary gear carrier and atraction cable fastened thereto.
 16. The adjustment device according toclaim 3, wherein said annular gear is formed in a housing of thegearbox.
 17. The adjustment device according to claim 3, furthercomprising a return spring exerting pretensioning in a direction of arange of adjustment of said gearbox.
 18. The adjustment device accordingto claim 3, wherein at least a portion of an end region of anon-internally toothed portion of said annular gear is comprised of adamping material.
 19. The adjustment device according to claim 3,further comprising a lumbar support wherein said lumbar support isadjustable in respect of at least one of its position and shape.
 20. Theadjustment device according to claim 19, characterised in that saidlumbar support has a curving element whose curvature is adjustable. 21.A gearbox operatively connected to a drive unit and adjustably connectedto a component of a seat, comprising: a sunwheel in a driven drivenrelationship with the drive unit; an annular gear; a planetary gear,wherein said planetary gear meshes with said sunwheel and said annulargear; and a planetary gear carrier, wherein said planetary gear carrierrotates concentrically with said sunwheel.
 22. The gearbox according toclaim 21, wherein said annular gear is an internally toothed annulargear.
 23. The adjustment device according to claim 22, wherein saidannular gear is internally toothed for a portion of its circumference.24. The adjustment device according to claim 23, wherein said planetarygear rolls on said internally toothed portion of said annular gear anddoes not roll on a non- internally-toothed portion of said annular gear.25. The adjustment device according to claim 24, wherein at least aportion of an end region of said non-internally toothed portion of saidannular gear is comprised of a damping material.
 26. The adjustmentdevice according to claim 24, wherein a surface portion of saidnon-internally toothed portion of said annular gear is comprised of adamping material.
 27. The adjustment device according to claim 21,further comprising a housing.
 28. The adjustment device according toclaim 27, wherein said annular gear is formed in said housing.
 29. Theadjustment device according to claim 21, further comprising a returnspring exerting a pretension in a direction of a range of adjustment ofthe gearbox.